Bioethanol is a promising biofuel for the energy transition, but its production faces the challenge of separating water from ethanol due to the formation of an azeotrope. Various technologies have been developed to address this issue, with adsorption using natural or synthetic zeolites through the Pressure Swing Adsorption (PSA) process being one of the most promising, efficient, and economical solutions. PSA allows for the obtaining of ethanol with high purity, and its efficiency and performance improve when optimized with robust control laws against disturbances. The aim of this work is the characterization of natural and synthetic zeolites implemented in a PSA plant for the production of bioethanol using a fractional-order integral state feedback control law to attenuate disturbances in the process feed and maintain the desired purity (99.5%) in compliance with international standards for use as a biofuel. This robust control law was demonstrated to be superior to other control strategies implemented in this complex PSA process, achieving a purity of over 0.99 molar fraction under disturbances and yielding a higher recovery of 92% with an energy efficiency of 93%. Increased water molecule adsorption along the column was achieved, from 2.93 m to 5.84 m , resulting in higher bioethanol production. • Zeolite type 3A exhibited greater water molecule adsorption compared to heulandite and clinoptilolite. • A bioethanol purity of 99% by weight was achieved from the azeotropic point using an experimental PSA plant. • The PSA process, employing automatic control laws, is more robust to disturbances, maintaining the desired purity. • Actional-order integral state feedback control allows for increased production and recovery of bioethanol with improved energy efficiency.
Sorcia-Vázquez et al. (Wed,) studied this question.